Tissue preservation

This outcome was consistent with a hypothesis that structural deterioration could have been a byproduct of microorganism activity. The higher lipid content in the poorly preserved tissue suggests that those lipids are primarily extrinsic, that is, that they were produced by bacteria and/or fungi. As the food source for such microorganisms, the protein within the bone may have been substantially altered in concert with the microstructure deterioration. The quantification of the changes to the organic fraction became our next focus of research. 

High antioxidative activity carvedilol has been shown in isolated rat heart mitochondria [297] and in the protection against myocardial injury in postischemic rat hearts [281]. Carvedilol also preserved tissue GSL content and diminished peroxynitrite-induced tissue injury in hypercholesterolemic rabbits [298]. Habon et al. [299] showed that carvedilol significantly decreased the ischemia-reperfusion-stimulated free radical formation and lipid peroxidation in rat hearts. Very small I50 values have been obtained for the metabolite of carvedilol SB 211475 in the iron-ascorbate-initiated lipid peroxidation of brain homogenate (0.28 pmol D1), mouse macrophage-stimulated LDL oxidation (0.043 pmol I 1), the hydroxyl-initiated lipid peroxidation of bovine pulmonary artery endothelial cells (0.15 pmol U1), the cell damage measured by LDL release (0.16 pmol l-1), and the promotion of cell survival (0.13 pmol l-1) [300]. SB 211475 also inhibited superoxide production by PMA-stimulated human neutrophils. 

Isoflurane (Forane) is a structural isomer of enflurane and produces similar pharmacological properties some analgesia, some neuromuscular blockade, and depressed respiration. In contrast, however, isoflurane is considered a particularly safe anesthetic in patients with ischemic heart disease, since cardiac output is maintained, the coronary arteries are dilated, and the myocardium does not appear to be sensitized to the effects of catecholamines. Also, blood pressure falls as a result of vasodilation, which preserves tissue blood flow. Isoflurane causes transient and mUd tachycardia by direct sympathetic stimulation this is particularly important in the management of patients with myocardial ischemia. 

Like glutaraldehyde, formaldehyde is an additive fixative used for preserving tissues for light microscopy (Hayat, 2000a). When formaldehyde reacts with an amino acid that... 

Technologies to preserve tissues and organs for transplantation and prevent tissue and organ rejection and for improvement of artificial organs and prostheses for replacing malfunctioning body parts should be identified.57 58... 

The versatility of immunophenotypic analysis has enhanced its usefulness. Immunophenotyping can be performed on a variety of specimens including cryop-reserved tissue sections, routinely preserved tissue sections, cells in suspension, tissue-touch preparations ( touch preps ), fine-needle aspiration smears, cytology thin preps and smears, as well as bone marrow aspirate smears. With the evolution of medical science and technical ability the number and types of antigens that can be detected in each type of preparation have greatly increased. Furthermore, as an additional result of these technical and scientific advances, immunophenotyping, particularly of routinely fixed tissue sections, can be performed reliably in many laboratories. 

Tissue specimens are fixed in formalin and subsequently embedded in paraffin in the majority of cases. While formalin fixation preserves tissue morphology, it also alters the three-dimensional structure of tissue proteins. This alteration can result in a modification of the antigen s epitopes and/or of its electrostatic charges (EC). The loss of an epitope results in an antigen s inability to react with the paratope of the antibody and can only be corrected by the restoration (retrieval) of the epitope. The reduction of net negative ECs of antigens decreases the avidity of the immune reaction and may be compensated for by prolonging the incubation time with the primary antibody (1) or the use of different antibody diluents (2). 

NOTE Formalin does not preserve tissue proteins by coagulation but it is thought to form cross links with basic amino acids. Ethanol and mercuric chloride-based fixatives are based on coagulation. With few exceptions retrieval should not be performed on ethanol fixed tissues. It should only be conducted with limited controlled protocols in mercuric-chloride-based fixatives. 

Tissue fixation The techniques used to evaluate tissue structure (e.g., light microscopy, confocal microscopy, or electron microscopy), will vary with the goals of the experiment. Proper tissue processing and fixation should focus on preserving tissue structure and tissue antigens. 

The collection of plant tissue is quite different from animal tissue collection. The discussion of collection of plant and animal tissue by Dessauer et al.2S is detailed and helpful. However, the recommendations for procedures unique to plant tissue collection are somewhat misleading and outdated, especially when tropical collections are involved. Plant tissue can now be collected and transported as either fresh tissue (leaves and/or shoot cuttings) or preserved tissue the latter either as cryopreserved tissue (liquid nitrogen or dry ice) or as dried tissue (air-dried, herbarium-dried, lyophilized, or chemically dried). Ambient-temperature liquid chemical preservation techniques (such as those routinely done for herbarium plant specimens in the tropics) so far have been ineffective in maintaining adequate yields of high-quality DNA.15 It should be stressed again that the manner of collecting plant tissue is dictated by several other factors what macromolecule (DNA, RNA, or isozymes) will be examined, what type of nucleic acid extraction method will be used (or, more impor-... 

Although the GLP Principles allow the disposal of specimens and samples, when their condition precludes further meaningful evaluation, the individual responsible for the archives has to pay attention also to the opposite clause of the Principles, namely the requirement that the storage conditions should preclude untimely deterioration. If for example, the jars containing preserved tissues cannot be sufficiently sealed, so that the preservative slowly evaporates, it lies in the responsibility of the archivist to periodically check these jars and to refill them with the respective preservative, if the need arises. Consequently, it would be considered a violation of the GLP Principles, if such specimens were just left to dry out, and the deteriorated specimens were then to be destroyed. 

Herkenham M, Pert CB (1982) Light microscopic localization of brain opiate receptors a general autoradiographic method which preserves tissue quality. J. Neuroscl, 2, 1129-1149. 

In diagnostic clinical medicine, DNA identification has been applied to investigations of patient tissue specimens obtained during biopsies or autopsies. Because of imaginative adaptations of DNA extraction techniques, the DNA contained in slides and preserved tissue specimens can now be investigated for evidence of infectious or genetic diseases. For example, in situ DNA hybridization is an ultrasensitive technique in which specific DNA probes are applied directly to tissue embedded in paraffin. (Paraffin-embedded tissue specimens are used in microscopic studies. Such slides can be stored... 

Many members of the aldehyde and ketone families are important as food and fragrance chemicals, medicinals, and agricultural chemicals. Methanal (formaldehyde) is used to preserve tissue. Ethanal causes the s)unptoms of a hangover and is oxidized to produce acetic acid commer-... 

Methods In situ hybridization (ISH) and PCR-based molecular methods are two highly sensitive molecular methods used to detect both viruses. Using ISH, we can study the viral persistence in preserved tissue structure. PGR-based methods allow to study different viral expression patterns and latent infection status. For PCR-based methods, viral DNA and/or mRNA is extracted from tissue or body fluids and followed by PGR or RT-PCR. 

Immunohistochemical localization of adducts can be accomplished using antiserum developed and characterized for quantitative immunoassays. The 3-(cystein-S-yl)aceta-minophen protein adduct is associated with the toxicity of the prototjqje hepatotoxin, acetaminophen. Immunohistochemical localization of this adduct is described to illustrate the technique as an adjunct to other methods in the assessment of toxicity. This method provides direct correlation between presence of adduct and morphologic evidence of cell injury. Microwave irradiation was pioneered as a fixation method to simultaneously preserve tissue structiu e and adduct antigenicity. 

Prehybridization protocols are designed to increase access of probe to the target while preserving tissue morphology. A balance has to be struck between the two processes because fixation (protem crosslmking) reduces probe penetration and, hence, hybridization efficiency. The procedure is carried out at room temperature. 

Bromo-2-nitropropane-1,3-diol Calcium disodium EDTA p-Chloro-m-cresol Dichlorophene Diiodomethyl tolylsulfone Dimethyl oxazolidine Laurtrimonium chloride Pine (Pinus palustris) oil Poly (hexamethylenebiguanide) hydrochloride Sodium 2-mercaptobenzothiazole 2-Thiocyanomethylthiobenzothiazole Tributyltin oxide 2,4,6-Trichlorophenol preservative, timber Zinc arsenite preservative, tissues... 

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